Hello,
The datasheet does not seem to mention a maximum PWM frequency, though it is implied to be 200kHz from page 9. Am I safe to assume that a PWM frequency of up to 200kHz will allow 8A continuous / 12A peak?
Further, dead time requirements are not mentioned in the datasheet. Am I safe to assume that the IC takes care of dead time / prevents shoot through?
Lastly, could I request that these items be explicitly added to the datasheet?
Cheers,
Scott
Hi @SHanson ,
Based on the graph on page 9, yes, it’s safe to assume that the maximum input PWM frequency to ensure the device operates within specs is 200kHz. Just as an FYI, based on the typical performance characteristics, the nominal switching frequency is 20kHz.
The IC does not have built in dead-time, so you will need to make sure there’s adequate dead-time based on your system requirements. The IC does have OCP that shuts down the FETs if short-circuit is detected, but it’s a priority to make sure your chosen dead-time is adequate via testing.
Thanks,
Rubas
Hi Rubas,
Thank you for the reply. Unfortunately I believe the dead time would be a function of the characteristics of the internal FETs you use in the IC, and it seems impossible to back calculate based on the datasheet provided.
Ie, even if no motor is connected, it could be possible for the high and low switches to allow current to pass from the power rail to ground.
Given that at 200khz a dead time of say 5ns would be fine, but a requirement of 500ns would impact the duty cycle beyond what I’d be comfortable with, I would really appreciate some more information here.
Passing the buck to the customer to test a Monolithic Power Systems design artefact does not fill me with confidence.